Stet

An open source, local-first document editor with an AI that marks up your writing like a human editor.

Highlights, circles, wavy underlines, margin notes — suggestions you can see and accept, not a chatbot that rewrites behind your back. Your documents are plain files on your disk. Bring your own API key.

▶ Try the live demo  ·  runs entirely in your browser, no install, no account

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Why Stet

Most “AI writing tools” either rewrite your text for you or bury edits in a chat panel. Stet treats the AI like a copy editor working on paper: it marks where something could be better and why, and the change only happens when you accept it.

• Local-first. Documents are real files on disk (~/Stet by default) — one .json per doc plus a readable .md sibling. Clear your browser cache, use incognito, switch machines: nothing is lost. No account, no server, no telemetry.
• Bring your own key. AI calls go browser → your provider (Anthropic, OpenAI, or Gemini) using a key you paste in Settings. It lives in localStorage only and never touches a Stet server — there isn’t one.
• Markup, not mutation. AI suggestions are ProseMirror decorations. Your document’s content changes only when you accept a suggestion.
• Calm, Craft-inspired design. A floating page, generous whitespace, light or dark (plus reading/forest/midnight themes). No shadows — depth comes from surface contrast and hairline borders.

Features

• ✍️ Rich text editor (TipTap) — headings, lists, quotes, code, links, emoji, images, page breaks
• 🤖 AI review — grammar fixes, style suggestions, highlights, and circled passages you accept or dismiss
• 🖊️ Human markup tools — highlight, colored underline, circle, all as real document marks
• 💬 Notes — Google-Docs-style comments anchored to text, in a right-side panel
• 🖼️ Images — insert, paste, or drag-and-drop; stored on disk beside your docs
• 📄 Pages & typography — continuous or paginated (A4/Letter), free-form width, four document fonts, text-size control
• 📁 Folders & library — a Home dashboard and a card-grid /documents view
• 📤 Export — Markdown, Word (.docx), HTML, plain text, and PDF
• 📥 Import — Markdown, text, HTML, and Word (.docx)
• 🌗 Themes — light, dark, midnight, reading, forest — all token-driven

Quick start

You need Node 20+.

git clone https://github.com/filu123/stet.git
cd stet
npm install
npm run dev

Open http://localhost:3000 and start writing. That’s it — documents are saved to ~/Stet automatically.

To use the AI features, open Settings (gear icon, top-right), choose a provider, and paste your API key.

Where your documents live

By default, Stet writes to ~/Stet. Point it somewhere else with an env var:

STET_DATA_DIR=~/Documents/Stet npm run dev

Each document is a pretty-printed <id>.json (the canonical source) plus a <slug>.<id>.md sibling you can read or grep. Folders are real subdirectories; images live in <STET_DATA_DIR>/images. Back it up like any other folder.

No server for your data. The Next.js app is the local server that reads and writes that folder. If you deploy Stet to an ephemeral host instead, it transparently falls back to in-browser storage (IndexedDB).

Deploy a hosted instance

For a shareable, no-install instance (like the live demo), deploy to Vercel and set STET_STORAGE_MODE=browser so documents persist in each visitor's own browser instead of a disappearing serverless disk:

Everything stays client-side and BYO-key — a hosted Stet never sees your documents or your API key.

Privacy

• No telemetry, no analytics, no accounts. Stet never phones home.
• Your API key is read from localStorage at call time and sent only to the provider you chose. It never enters a document, an export, a log, or an error message.
• Your writing stays on your machine. The only text that leaves is what you send to your AI provider when you run a review — using your own key, under their policy.

Tech

Next.js 16 (App Router, Turbopack) · TypeScript (strict) · Tailwind v4 · TipTap / ProseMirror · Zustand · Vitest. No backend service, no database server.

npm run dev     # start the dev server
npm run lint    # ESLint (zero warnings)
npm run build   # production build
npm test        # Vitest unit tests

Contributing

Stet is developed by a single maintainer with a specific vision, and every change is reviewed and merged by the maintainer. Pull requests are welcome but not guaranteed to be merged — please open an issue to discuss first so we don’t both waste effort. See CONTRIBUTING.md before opening one.

License

GNU AGPL-3.0. You’re free to use, study, self-host, and modify Stet. If you run a modified version as a network service, you must make your source available under the same license. This keeps Stet open for everyone and prevents it from being taken closed-source.